SYMPOSIUM
Journal of Diabetes Science and Technology
Volume 4, Issue 4, July 2010 © Diabetes Technology Society
Thermal Imaging Today and Its Relevance to Diabetes Francis Ring, D.Sc., FIPEM, FRPS
Abstract From the historic and simple assessment of temperature by the clinical thermometer, modern infrared technology has opened up new perspectives, especially in the use of thermal imaging to map body surface temperature with a remote sensing camera. Since the 1960s, there is now a greater understanding of thermal physiology and the relationship between skin temperature and blood perfusion. Furthermore, the examination technique, and the advantages of computer-aided digital imaging has greatly improved the reliability of this technology in medicine. Studies in diabetology have shown the value of this new facility and its relevance to clinical assessment of peripheral perfusion and tissue viability. J Diabetes Sci Technol 2010;4(4):857-862
Introduction
T
he association between disease and temperature is as old as medicine itself. However, the early physicians had only primitive means of assessing the presence of fever in their patients, mostly by using the natural sense of touch. From the 17th century onward, thermometers were developed, but it was not until the 18th century that Dr. Carl Wunderlich in Leipzig, Germany, systematically studied the course of temperature in his patients and could monitor the progress of fever. He developed the clinical thermometer that has been used universally in medicine for some 200 years.1
Thermal imaging is a technique that uses infrared radiation but is not widely used in routine medical diagnostics. First uses were made in the 1960s, with large and noisy scanners. These were employed in some research studies and applied to the noninvasive study of human skin temperature.2 The human body is an efficient thermal system. We are entirely dependent on the ability of the body to self-regulate human body temperature. Vital organs are dependent on regular perfusion of blood carrying oxygen, and our ability to survive in arctic or tropical conditions is dependent on the adjustments in human circulation to the organs of the body, of which the heart is the central pumping mechanism.
The last half century has brought dramatic changes in the way in which the human body can be investigated. In particular, we now have many different imaging techniques. Initially, the microscope, followed by radiology with the use of X rays, were the most useful tools in medicine. Today, a wider range of different physical energies from ultrasound to magnetic resonance is available that opens up greater opportunities for diagnostic imaging.
One of the key factors in thermoregulation of the human body is the skin, which is the dynamic interface between the body and its environment. In excessive heat, the need to lose heat is accelerated by sweating, which evaporates and cools the skin. In very cold conditions, the peripheral
Author Affiliation: Medical Imaging Research Unit, Faculty of Advanced Technology, University of Glamorgan, Pontypridd, United Kingdom Keywords: amputation, diabetes mellitus, infrared, skin temperature, thermal imaging, ulceration Corresponding Author: Francis Ring, D.Sc., FIPEM, FRPS, Medical Imaging Research Unit, Faculty of Advanced Technology, University of Glamorgan, Pontypridd CF37 1DL, United Kingdom; email address
[email protected] 857
Thermal Imaging Today and Its Relevance to Diabetes
Ring
Thermal Imaging Technique
blood vessels constrict, reducing the opportunity for blood cooling at the body surface.3
All medical imaging procedures have benefited from the use of modern digital technology. A reliable thermal imaging system will be used online with a computer that will be operating specialized software. This will be able to indicate to the operator when the camera is stable and ideally will provide confirmation from a temperature reference source that the calibration is at the correct level. The examination should be performed in a temperature-controlled environment with a humidity of
